Systems and methods for glass manufacturing

ABSTRACT

Submerged combustion systems and methods of use to produce glass. One system includes a submerged combustion melter having a roof, a floor, a wall structure connecting the roof and floor, and an outlet, the melter producing an initial foamy molten glass. One or more non-submerged auxiliary burners are positioned in the roof and/or wall structure and configured to deliver combustion products to impact at least a portion of the bubbles with sufficient force and/or heat to burst at least some of the bubbles and form a reduced foam molten glass.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of prior pending U.S. application Ser.No. 14/606,875, filed Jan. 27, 2015 which is a division of U.S.application Ser. No. 13/268,130 filed Oct. 7, 2011, now U.S. Pat. No.9,021,838 issued May 5, 2015. This application is related to Applicant'sUnited States non-provisional U.S. application Ser. No. 12/817,754,filed Jun. 17, 2010, now U.S. Pat. No. 8,769,992, issued Jul. 8, 2014;Ser. No. 12/888,970, filed Sep. 23, 2010, now U.S. Pat. No. 8,650,914,issued Feb. 18, 2014; Ser. No. 13/267,990, filed Oct. 7, 2011, now U.S.Pat. No. 8,997,525 issued Apr. 7, 2015; Ser. No. 13/268,028, filed Oct.7, 2011, now U.S. Pat. No. 8,875,544 issued Nov. 4, 2014; and Ser. No.13/268,098, filed Oct. 7, 2011, now U.S. Pat. No. 8,707,740 issued Apr.29, 2014, all of which are incorporated herein by reference.

BACKGROUND INFORMATION

Technical Field

The present disclosure relates generally to the field of combustionfurnaces and methods of use to produce glass, and more specifically tosystems and methods for reducing foam or its impact during manufactureof glass using submerged combustion melters.

Background Art

Submerged combustion melting (SCM) involves melting glass batchmaterials to produce molten glass by passing oxygen, oxygen-air mixturesor air along with a liquid, gaseous fuel, or particulate fuel in theglass batch, directly into a molten pool of glass usually throughburners submerged in a glass melt pool. The introduction of high flowrates of oxidant and fuel into the molten glass, and the expansion ofthe gases cause rapid melting of the glass batch and much turbulence.However, one drawback to submerged combustion is the tendency of themolten glass to foam. The foam may stabilize in a top layer when themolten mass is routed through conditioning and/or distributionchannels/systems downstream of the submerged combustion melter. The foamlayer may impede the ability to apply heat to the glass using combustionburners, and may also impede the rate at which further bubbles in themelt rise and thus effect expulsion of the bubbles and mass flow rate ofthe melt in the channels. In extreme cases, the foam generated mayinterfere with the traditional energy application methods employed,which may cause systems to require shutdown, maintenance and may resultin a process upset. Attempts to reduce the foam problem through processadjustments have not met with complete success in reducing foam to anacceptable amount.

It would be an advance in the glass manufacturing art if foam could bereduced, or the effect of the foam reduced, during glass manufacturedusing a submerged combustion melter and methods.

SUMMARY

In accordance with the present disclosure, systems and methods aredescribed which reduce or overcome one or more of the above problems.

A first aspect of the disclosure is a system comprising:

a submerged combustion melter comprising a floor, a roof, and a wallstructure connecting the floor and roof, the melter comprising one ormore submerged combustion burners and a molten glass outlet, the melterconfigured to produce an initial foamy molten glass having a density andcomprising bubbles, at least some of the bubbles forming a bubble layeron top of the foamy molten glass; and

one or more non-submerged auxiliary burners positioned in the roofand/or wall structure and configured to deliver their combustionproducts to impact at least a portion of the bubbles in the bubble layerwith sufficient force and/or heat to burst at least some of the bubblesand form a reduced foam molten glass.

A second aspect of the disclosure is a system comprising:

a submerged combustion melter comprising a floor, a roof, and a wallstructure connecting the floor and roof, the melter comprising one ormore submerged combustion burners and a molten glass outlet, the melterconfigured to produce an initial foamy molten glass having a density andcomprising bubbles, at least some of the bubbles forming a bubble layeron top of the foamy molten glass; and

a downstream component fluidly connected to the melter for accepting atleast a portion of the foamy molten glass, the downstream componentcomprising a flow channel, a downstream component roof, and a downstreamcomponent wall structure connecting the downstream component flowchannel and downstream component roof, the downstream componentcomprising one or more non-submerged downstream component auxiliaryburners positioned in the downstream component roof and/or downstreamcomponent wall structure and configured to deliver their combustionproducts to impact at least a portion of bubbles in the bubble layer onthe foamy molten glass with sufficient force and/or heat to burst atleast some of the bubbles.

A third aspect of the disclosure is a system comprising:

a submerged combustion melter comprising a floor, a roof, and a wallstructure connecting the floor and roof, the melter comprising one ormore submerged combustion burners and a molten glass outlet, the melterconfigured to produce an initial foamy molten glass having a density andcomprising bubbles, at least some of the bubbles forming a bubble layeron top of the foamy molten glass;

one or more non-submerged auxiliary burners positioned in the roofand/or wall structure and configured to deliver combustion products toimpact at least a portion of the bubbles in the bubble layer withsufficient force and heat to burst at least some of the bubbles and forma reduced foam molten glass; and

a downstream component fluidly connected to the melter for accepting atleast a portion of the reduced foam molten glass, the downstreamcomponent comprising a flow channel, a downstream component roof, and adownstream component wall structure connecting the downstream componentflow channel and downstream component roof, the downstream componentcomprising one or more non-submerged downstream component auxiliaryburners positioned in the downstream component roof and/or downstreamcomponent wall structure and configured to deliver their combustionproducts to impact at least a portion of bubbles remaining in the bubblelayer on the reduced foam molten glass with sufficient force and/or heatto burst at least some of the remaining bubbles.

A fourth aspect of the disclosure is a method comprising:

melting glass-forming materials in a submerged combustion meltercomprising a floor, a roof, and a wall structure connecting the floorand roof, the melter comprising one or more submerged combustion burnersand a molten glass outlet;

producing an initial foamy molten glass having a density and comprisingbubbles, at least some of the bubbles forming a bubble layer on top ofthe foamy molten glass; and

routing combustion products from one or more non-submerged auxiliaryburners positioned in the roof and/or wall structure to impact at leasta portion of the bubbles in the bubble layer with sufficient forceand/or heat to burst at least some of the bubbles and form a reducedfoam molten glass.

A fifth aspect of the disclosure is a method comprising:

melting glass-forming materials in a submerged combustion meltercomprising a floor, a roof, and a wall structure connecting the floorand roof, the melter comprising one or more submerged combustion burnersand a molten glass outlet;

producing an initial foamy molten glass having a density and comprisingbubbles, at least some of the bubbles forming a bubble layer on top ofthe foamy molten glass; and routing at least a portion of the foamymolten glass and bubble layer into a downstream component fluidlyconnected to the melter, the downstream component comprising a flowchannel, a downstream component roof, and a downstream component wallstructure connecting the downstream component flow channel anddownstream component roof; and

routing combustion products from at least one downstream componentnon-submerged auxiliary burners positioned in the downstream componentroof and/or downstream component wall structure to impact at least aportion of bubbles in the bubble layer on the foamy molten glass withsufficient force and/or heat to burst at least some of the bubbles.

A sixth aspect of the disclosure is a method comprising:

melting glass-forming materials in a submerged combustion meltercomprising a floor, a roof, and a wall structure connecting the floorand roof, the melter comprising one or more submerged combustion burnersand a molten glass outlet;

producing an initial foamy molten glass having a density and comprisingbubbles, at least some of the bubbles forming a bubble layer on top ofthe foamy molten glass;

routing combustion products from one or more non-submerged auxiliaryburners positioned in the roof and/or wall structure to impact at leasta portion of the bubbles in the bubble layer with sufficient forceand/or heat to burst at least some of the bubbles and form a reducedfoam molten glass; and

routing at least a portion of the reduced foam molten glass to adownstream component fluidly connected to the melter, the downstreamcomponent comprising a flow channel, a downstream component roof, and adownstream component wall structure connecting the downstream componentflow channel and downstream component roof; and

routing combustion products from one or more non-submerged downstreamcomponent auxiliary burners positioned in the downstream component roofand/or downstream component wall structure to impact at least a portionof bubbles remaining in the bubble layer on the reduced foam moltenglass with sufficient force and/or heat to burst at least some of theremaining bubbles.

Systems and methods of the disclosure will become more apparent uponreview of the brief description of the drawings, the detaileddescription of the disclosure, and the claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The manner in which the objectives of the disclosure and other desirablecharacteristics can be obtained is explained in the followingdescription and attached drawings in which:

FIG. 1A is a schematic cross-sectional view of one embodiment of anauxiliary burner useful in systems and methods of this disclosure;

FIGS. 1B and 1C are schematic cross-sectional views of the auxiliaryburner of FIG. 1A along the lines A-A and B-B, respectively;

FIG. 2 is a schematic cross-sectional view of another embodiment of anauxiliary burner useful in systems and methods of this disclosure;

FIG. 3 is a cross-sectional view of a liquid-cooled version of theburner of FIG. 2;

FIG. 4 is a schematic cross-sectional view of another auxiliary burnerincluding a ceramic burner block useful in certain embodiments ofsystems and methods of the present disclosure;

FIG. 5 is a schematic diagram of a portion of the burner of FIG. 4,illustrating certain dimensions of the burner;

FIG. 6 is a schematic perspective view of a system embodiment of thepresent disclosure;

FIG. 7 is a schematic perspective view of another system embodiment ofthe present disclosure; and

FIGS. 8, 9, and 10 are logic diagrams of three method embodiments of thepresent disclosure.

It is to be noted, however, that the appended drawings are not to scaleand illustrate only typical embodiments of this disclosure, and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective embodiments.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to providean understanding of the disclosed systems and methods. However, it willbe understood by those skilled in the art that the systems and methodscovered by the claims may be practiced without these details and thatnumerous variations or modifications from the specifically describedembodiments may be possible and are deemed within the claims. All U.S.published patent applications and U.S. patents referenced herein arehereby explicitly incorporated herein by reference. In the eventdefinitions of terms in the referenced patents and applications conflictwith how those terms are defined in the present application, thedefinitions for those terms that are provided in the present applicationshall be deemed controlling.

As explained briefly in the Background, one drawback to submergedcombustion is the tendency of the molten glass to foam, either fromglass-forming reactions, combustion products, or both. The foam maystabilize in a top layer when the molten mass is routed throughequipment downstream of the submerged combustion melter, such asforehearths, conditioning channels, distribution channels, and the like.The foam layer may impede the ability to apply heat to the glass usingcombustion burners in the melter and in such downstream equipment, andmay also impede the rate at which further bubbles in the melt rise andthus effect expulsion of the bubbles and mass flow rate of the melt inthe channels. In extreme cases, the foam generated may interfere withthe traditional energy application methods employed, which may causesystems to require shutdown, maintenance and may result in a processupset. Attempts to reduce the foam problem through process adjustmentshave not met with complete success in reducing foam to an acceptableamount.

Applicants have discovered systems and methods that may reduce oreliminate such problems.

Various terms are used throughout this disclosure. “Submerged” as usedherein means that combustion gases emanate from burners under the levelof the molten glass; the burners may be floor-mounted, wall-mounted, orin melter embodiments comprising more than one submerged combustionburner, any combination thereof (for example, two floor mounted burnersand one wall mounted burner).

The terms “foam” and “foamy” include froths, spume, suds, heads, fluffs,fizzes, lathers, effervesces, layer and the like. The term “bubble”means a thin, shaped, gas-filled film of molten glass. The shape may bespherical, hemispherical, rectangular, ovoid, and the like. Gas in thegas-filled bubbles may comprise oxygen or other oxidants, nitrogen,argon, noble gases, combustion products (including but not limited to,carbon dioxide, carbon monoxide, NO_(x), SO_(x), H₂S, and water),reaction products of glass-forming ingredients (for example, but notlimited to, sand (primarily SiO₂), clay, limestone (primarily CaCO₃),burnt dolomitic lime, borax and boric acid, and the like. Bubbles mayinclude solids particles, for example soot particles, either in thefilm, the gas inside the film, or both.

As used herein the term “combustion gases” means substantially gaseousmixtures of combusted fuel, any excess oxidant, and combustion products,such as oxides of carbon (such as carbon monoxide, carbon dioxide),oxides of nitrogen, oxides of sulfur, and water. Combustion products mayinclude liquids and solids, for example soot and unburned liquid fuels.

“Oxidant” as used herein includes air and gases having the same molarconcentration of oxygen as air, oxygen-enriched air (air having oxygenconcentration of oxygen greater than 21 mole percent), and “pure”oxygen, such as industrial grade oxygen, food grade oxygen, andcryogenic oxygen. Oxygen-enriched air may have 50 mole percent or moreoxygen, and in certain embodiments may be 90 mole percent or moreoxygen. Oxidants may be supplied from a pipeline, cylinders, storagefacility, cryogenic air separation unit, membrane permeation separator,or adsorption unit.

The term “fuel”, according to this disclosure, means a combustiblecomposition comprising a major portion of, for example, methane, naturalgas, liquefied natural gas, propane, atomized oil or the like (either ingaseous or liquid form). Fuels useful in the disclosure may compriseminor amounts of non-fuels therein, including oxidants, for purposessuch as premixing the fuel with the oxidant, or atomizing liquid fuels.As used herein the term “fuel” includes gaseous fuels, liquid fuels,flowable solids, such as powdered carbon or particulate material, wastematerials, slurries, and mixtures or other combinations thereof. Whenthe fuel comprises gaseous fuel, the gaseous fuel may be selected fromthe group consisting of methane, natural gas, liquefied natural gas,propane, carbon monoxide, hydrogen, steam-reformed natural gas, atomizedoil or mixtures thereof.

The sources of oxidant and fuel may be one or more conduits, pipelines,storage facility, cylinders, or, in embodiments where the oxidant isair, ambient air. Oxygen-enriched oxidants may be supplied from apipeline, cylinder, storage facility, cryogenic air separation unit,membrane permeation separator, or adsorption unit such as a vacuum swingadsorption unit.

Conduits used in burners useful in the systems and methods of thepresent disclosure may be comprised of metal, ceramic, ceramic-linedmetal, or combination thereof. Suitable metals include stainless steels,for example, but not limited to, 306 and 316 steel, as well as titaniumalloys, aluminum alloys, and the like. Suitable materials for therefractory cooled panels, melter and channel refractory liners, andrefractory burner blocks (if used) are fused zirconia (ZrO₂), fused castAZS (alumina-zirconia-silica), rebonded AZS, or fused cast alumina(Al₂O₃). The burner and melter geometry, and type of glass to beproduced may dictate the choice of a particular material, among otherparameters.

The terms “cooled” and “coolant” may include use of any heat transferfluid and may be any gaseous, liquid, or some combination of gaseous andliquid composition that functions or is capable of being modified tofunction as a heat transfer fluid. Gaseous heat transfer fluids may beselected from air, including ambient air and treated air (for example,air treated to remove moisture), inorganic gases, such as nitrogen,argon, and helium, organic gases such as fluoro-, chloro- andchlorofluorocarbons, including perfluorinated versions, such astetrafluoromethane, and hexafluoroethane, and tetrafluoroethylene, andthe like, and mixtures of inert gases with small portions of non-inertgases, such as hydrogen. Heat transfer liquids may be selected fromliquids that may be organic, inorganic, or some combination thereof, forexample, salt solutions, glycol solutions, oils and the like. Otherpossible heat transfer fluids include steam (if cooler than the expectedglass melt temperature), carbon dioxide, or mixtures thereof withnitrogen. Heat transfer fluids may be compositions comprising both gasand liquid phases, such as the higher chlorofluorocarbons.

Certain fluid-cooled auxiliary burners useful in systems and methods ofthis disclosure may include first and second concentric conduits, thefirst conduit fluidly connected at one end to a source of fuel, thesecond conduit fluidly connected to a source of oxidant, and a thirdsubstantially concentric conduit comprising a first end, a second end,and an internal surface, the internal surface of the third conduitforming, with an exterior surface of the second conduit, a secondaryannulus external to a primary annulus between the first and secondconduits. The first end of the third conduit may extend beyond the firstend of the second conduit, the first end of the second conduit mayextend beyond the first end of the first conduit, and the secondaryannulus may be capped by an end cap connecting the first end of thesecond conduit and the first end of the third conduit.

In certain systems one or more of the non-submerged auxiliary burnersmay comprise a fuel inlet conduit having an exit nozzle, the conduit andnozzle inserted into a cavity of a ceramic burner block, the ceramicburner block in turn inserted into either the roof or the wallstructure, or both the roof and wall structure.

In certain systems, one or more of the non-submerged auxiliary burnersmay be adjustable with respect to direction of flow of the combustionproducts. Adjustment may be via automatic, semi-automatic, or manualcontrol. Certain system embodiments may comprise an auxiliary burnermount that mounts the auxiliary burner in the wall structure or roofcomprising a refractory, or refractory-lined ball joint. Other burnermounts may comprise rails mounted in slots in the wall or roof. In yetother embodiments the auxiliary burners may be mounted outside of themelter or downstream component, on supports that allow adjustment of thecombustion products flow direction. Useable supports include thosecomprising ball joints, cradles, rails, and the like.

Certain systems may comprise a downstream component fluidly connected tothe melter for accepting at least a portion of the reduced foam moltenglass, the downstream component comprising a flow channel, a downstreamcomponent roof, and a downstream component wall structure connecting theflow channel and downstream component roof. Certain systems may compriseone or more non-submerged downstream component auxiliary burnerspositioned in the downstream component roof and/or downstream componentwall structure and configured to deliver their combustion products toimpact at least a portion of bubbles remaining in the bubble layer onthe reduced foam molten glass flowing through the downstream component,with sufficient force and/or heat to burst at least some of theremaining bubbles.

In certain systems at least one of the downstream component auxiliaryburners may be adjustable with respect to direction of flow of thecombustion products from the downstream component auxiliary burner.

Certain systems may comprise one or more downstream component auxiliaryburners protruding through the wall structure and one or more auxiliaryburners protruding through the roof of the downstream component.

In certain systems and methods the auxiliary burners in the melterand/or the auxiliary burners in the downstream component may beconfigured to have a fuel velocity ranging from about 150 ft./second toabout 1000 ft./second (about 46 meters/second to about 305meters/second) and an oxidant velocity ranging from about 150 ft./secondto about 1000 ft./second (about 46 meters/second to about 305meters/second). The fuel and oxidant velocities may be the same ordifferent in a given burner, and from burner to burner.

In certain systems and methods the downstream component may be selectedfrom the group consisting of a distribution channel, a conditioningchannel, and a forehearth.

Certain system and method embodiments of this disclosure may includesubmerged combustion melters comprising fluid-cooled panels. In yetother embodiments a feed slot may be provided that may be covered andintegral with a fluid-cooled panel of a wall of the melter, such asdisclosed in Applicant's U.S. Pat. No. 8,650,914. In certain otherembodiments, the slot may be integral with an exhaust port or roof ofthe melter. In certain embodiments, the slot may comprise one or morehinged doors or panels. In certain other embodiments the slot maycomprise one or more sliding doors or panels. Certain embodiments maycomprise both hinged and sliding doors or panels. The hinged and slidingdoors may be water cooled, or cooled by other fluids.

In certain system and method embodiments, he submerged combustion meltermay include one or more submerged combustion burners comprising one ormore oxy-fuel combustion burners, such as described in Applicant's U.S.Pat. No. 8,875,544.

Certain system and method embodiments of this disclosure may becontrolled by one or more controllers. For example, burner combustion(flame) temperature may be controlled by monitoring one or moreparameters selected from velocity of the fuel, velocity of the primaryoxidant, mass and/or volume flow rate of the fuel, mass and/or volumeflow rate of the primary oxidant, energy content of the fuel,temperature of the fuel as it enters the burner, temperature of theprimary oxidant as it enters the burner, temperature of the effluent,pressure of the primary oxidant entering the burner, humidity of theoxidant, burner geometry, combustion ratio, and combinations thereof.Certain systems and methods of this disclosure may also measure and/ormonitor feed rate of batch or other feed materials, such as glass batch,cullet, mat or wound roving, mass of feed, and use these measurementsfor control purposes. Exemplary systems and methods of the disclosuremay comprise a combustion controller which receives one or more inputparameters selected from velocity of the fuel, velocity of oxidant, massand/or volume flow rate of the fuel, mass and/or volume flow rate ofoxidant, energy content of the fuel, temperature of the fuel as itenters the burner, temperature of the oxidant as it enters the burner,pressure of the oxidant entering the burner, humidity of the oxidant,burner geometry, oxidation ratio, temperature of the burner combustionproducts, temperature of melt, and combinations thereof, and may employa control algorithm to control combustion temperature based on one ormore of these input parameters.

Certain system and method embodiments may comprise using vibrationand/or oscillation of the submerged combustion melter to predict meltviscosity and/or other properties of the initial foamy melt emanatingfrom the melter, as disclosed in Applicant's U.S. Pat. No. 8,973,400.

Certain other systems and methods may comprise using a submergedcombustion melter comprising a large diameter exhaust port connecting toa large diameter chamber positioned between the melting chamber and anexhaust stack, as disclosed in Applicant's U.S. Pat. No. 8,707,740.Certain melters of this type may be devoid of a sump.

Yet other systems and methods may include a cooling and annealing lehrdownstream of the melter outlet, the lehr having an inlet and an outlet,and a transport apparatus allowing movement of the initial foamy moltenglass through the lehr to a processing apparatus, as described inApplicant's U.S. Pat. No. 8,997,525. Certain systems and methods mayroute a denser flow of molten glass to a production apparatus formanufacturing dense glass products, the production apparatus selectedfrom the group consisting of continuous fiber production apparatus,discontinuous fiber production apparatus, and glass shaping apparatus.

Specific non-limiting system and method embodiments in accordance withthe present disclosure will now be presented in conjunction with FIGS.1-10. The same numerals are used for the same or similar features in thevarious figures. In the views illustrated in FIGS. 1-7, it will beunderstood in each case that the figures are schematic in nature, andcertain conventional features are not illustrated in order to illustratemore clearly the key features of each embodiment.

FIG. 1A is a schematic, partially exploded cross-sectional view of oneembodiment 100 of an auxiliary burner useful in systems and methods ofthis disclosure. FIGS. 1B and 1C are schematic cross-sectional views ofauxiliary burner 100 of FIG. 1A along the lines 1B-1B and 1C-1C,respectively. Auxiliary burner embodiment 100 includes an oxidantconduit 10 having a large outer diameter end 11 and an exit end 17, aswell as a smaller outer diameter portion 13. An inner concentric fuelconduit 12 is provided having a fuel exit end 18, and an inlet end 25having threads for fitting a bushing 23 thereon. Bushing 23 may includea quick connect/disconnect feature, allowing a hose of other source offuel to be quickly attached to and detached from bushing 23. A connector14 allows a hose or other source of oxidant to be connected, for exampleby threads or a quick connect/disconnect feature 27, to auxiliary burnerembodiment 100.

Extending between fuel conduit 12 and oxidant conduit 13 are threespacers 15 spaced about 120 degree apart as illustrated in FIG. 1B.Spacers 15 provided strength to the burners, as well as help tostabilize the flame emanating from the burners.

An angle α is indicated in FIG. 1A and denotes the taper angle oftapered nozzle section 16 of fuel conduit 12. Nozzle 16 may be aseparate component or may be integral with conduit 12 (the latterversion is illustrated). Angle α may range from about 3 to about 45degrees.

FIG. 2 is a schematic cross-sectional view of another embodiment 200 ofan auxiliary burner useful in systems and methods of this disclosure,embodiment 200 differing from embodiment 100 only in that oxidantconduit 10 extends the entire length of burner embodiment 200. In otherwords, there is no small outer diameter portion 13 as in embodiment 100.

Both auxiliary burner embodiments 100 and 200 illustrated schematicallyin FIGS. 1 and 2 are high momentum burners. For example, embodiment 100may comprise a nominal ¼-inch stainless steel Schedule 40 pipe forconduit 12 and a nominal ¾-inch stainless steel Schedule 40 pipe forconduit 10 (turned down to 0.092-inch outer diameter (OD) in section13). Nominal ¼-inch Schedule 40 pipe has an external diameter of 0.54inch (1.37 cm) and an internal diameter of 0.36 inch (0.91 cm), whilenominal ¾-inch Schedule 40 pipe has an external diameter of 1.05 inch(2.67 cm) and internal diameter of 0.82 inch (2.08 cm). Embodiment 200,a slightly higher momentum version, may comprise a nominal ⅛-inchstainless steel Schedule 40 tube for conduit 12 and a nominal ½-inchstainless steel Schedule 40 conduit for oxidant conduit 10. Nominal⅛-inch Schedule 40 pipe has an external diameter of 0.41 inch (1.04 cm)and an internal diameter of 0.27 inch (0.69 cm), while nominal ½-inchSchedule 40 pipe has an external diameter of 0.84 inch (2.13 cm) andinternal diameter of 0.62 inch (1.57 cm). The selection of conduitschedule dictates the annular distance between the OD of conduit 12 andinternal diameter (ID) of conduit 10, and therefore the length ofspacers 15. Connection 14 may be an inch or two (about 2.5 cm to about 5cm) from burner cold end 21. These dimensions are merely examples, asany arrangement that produces the desired momentum and heat will besuitable, and within the skills of the skilled artisan in possession ofthis disclosure.

FIG. 3 is a cross-sectional view of a liquid-cooled embodiment 300 ofauxiliary burner embodiment 200 of FIG. 2, including a third concentricconduit 30 creating an annular region 33 between oxidant conduit 10 andconduit 30. Connections 29 and 31 allow inflow and outflow, respectivelyof cooling fluid. Embodiment 300 further includes a burner extension 32,as more fully described in Applicant's U.S. Pat. No. 8,875,544.

FIG. 4 is a schematic cross-sectional view of another auxiliary burnerembodiment 400 including a ceramic burner block useful in certainembodiments of systems and methods of the present disclosure. Embodiment400 includes an oxidant conduit 14 connecting to an oxidant plenum 20.Oxidant plenum 20 routes oxidant between the OD of fuel conduit 12 andan inner surface 22 of a cavity in a ceramic burner block 4. Burnerblock 4 includes a hot end 6 having an exit 8 for combustion products,and includes an internal surface having a straight portion 26 and atapered portion 28, where tapered portion 28 forms a combustion chamber34. Straight portion 26 forms a chamber 35 (FIG. 5) in which ispositioned tapered nozzle section 16 of fuel conduit 12.

FIG. 5 is a schematic diagram of a portion of the burner of FIG. 4,illustrating certain dimensions of auxiliary burner embodiment 400.Length L_(s) is the length of chamber 35 defined by straight section 26of inner surface 22 of the ceramic block cavity. L_(s) may range fromabout 0.5 inch to about 3 inches or more (from about 1.3 cm to about 7.6cm or more). Length L_(c) is the length of tapered section 28 of ceramicblock 4, and may range from about 5 inches to about 25 inches or more(from about 13 cm to about 64 cm or more). D_(s) is the diameter ofchamber 35, and depends on the external diameter of conduit 12, but maygenerally range from about 3 inches to about inches 10 inches or more(from about 7.62 cm to about 25 cm or more). D_(c) is the diameter ofchamber 34 at its exit, and may range from about 5 inches to about 25inches or more (from about 13 cm to about 64 cm). Angle β, which is theangle of tapered section 28 of ceramic burner block 4, may range fromabout 3 degrees to about 45 degrees or more, depending on the amount offoam present to be moved and positioning of the auxiliary burner in themelter.

FIG. 6 is a schematic perspective view, partially in phantom, of asystem embodiment 600 of the present disclosure. System embodiment 600comprises two auxiliary burners 302, 304 mounted in ports 301, 303,respectively, in a sidewall 310 of a submerged combustion (“SC”) melter602. Also included is a third auxiliary burner 306 mounted in a port 305in a roof 320 of SC melter 602. SC melter 602 further includes a feedend wall 308, floor 312 through which are mounted four SC burners 314,316, 318, and 319. The four SC burners in this embodiment are positionedin a square pattern. Burners 314, 316, 318, and 319 are shown partiallyin phantom as their bodies are under SC melter floor 312.

Roof 320 is illustrated schematically as having a cut-out portion 328,making it possible to view the internals of SC melter 602. In accordancewith embodiments of the present disclosure, flame and/or combustionproducts 322, 324 from sidewall-mounted auxiliary wall burners 302, 304,and flame and/or combustion products 326 from roof-mounted auxiliaryburner 306 are shown impinging on and either bursting some of thebubbles in a layer of bubbles 330, and/or heating the bubble layersufficiently to burst at least some of the bubbles. The film forming theoutside surfaces of the bubbles, formed as they are from liquefiedglass-forming materials, then flows back into the bulk of the moltenmaterial. It should be noted that embodiment 600 is merely illustrative,and that certain embodiments may have only one auxiliary burner, forexample only auxiliary burner 302, or only auxiliary burner 306.

Also illustrated in FIG. 6 are fuel supply conduits 332, 334, andoxidant supply conduits 336, 338, as well as respective flow controlvalves 340A-D. Conduits 332, 334, 336, and 338 may connect to theirrespective burner conduits via threaded fittings, quickconnect/disconnect fittings, hose fittings, and the like.

Another feature of systems and methods of the present disclosure isillustrated schematically in FIG. 6 and more particularly FIG. 7. Themolten glass produced in SC melter 602 may produce a reduced foam moltenglass that exits into a downstream component 700, which may be adistribution channel, conditioning channel, forehearth, or otherchannel. As the perspective view of FIG. 6 illustrates, and thecross-sectional view of FIG. 7 further illustrates, three auxiliaryburners are illustrated in downstream component 700, comprising twosidewall auxiliary burners 750, 752, and a third roof-mounted auxiliaryburner 754. It should be noted that only one auxiliary burner may beneeded in certain embodiments. Auxiliary burners 750, 752 are notillustrated as being position adjustable, although they could be.Auxiliary burner 754 is illustrated as position adjustable through aport 755, but in certain other embodiments it may not be so.

Referring more particularly to FIG. 7, forehearth 700 may include agenerally U-shaped channel or trough 702 of refractory materialsupported by a metallic superstructure 704. Trough 702 sits upon and issurrounded by insulating bricks 706 which are in turn supported bymetallic superstructure 704. A roof portion 708 covers channel or trough702 and includes opposed sides 710 formed by burner blocks 712 and roofblocks 714 extending over trough 702 between opposed burner blocks 712.Insulating bricks 716 may be provided about the outer periphery of roofblocks 714. Molten glass 717 of reduce foam content flows along trough702 as shown. Roof block 714 may include two spaced projections 718which extend downward toward the reduced foam molten glass 717 below thecenterline of the burner blocks. Spaced projections 718 form a centralchannel 720 over the central portion of the stream of molten glass 717and side channels 722 and 724 over respective side portions of thereduced foam molten glass stream. As is typical in forehearth design,cooling air may be provided along central channel 720.

Auxiliary burners 750 and 752 are mounted in burner blocks 712 with theforward end 726 of each burner extending into an aperture 728 in eachburner block 712. Quick disconnects (not illustrated in FIG. 7) foroxidant and fuel streams may be provided for each burner 750, 752 andpositioned outside its respective burner block 712 to enable the fuellines and oxidant lines to be attached thereto. Bubbles 730 remaining inmolten glass may rise in the molten glass and help to produce ormaintain a foam layer 719, or foam layer 719 might be in part left overfrom the SC melter 602 (FIG. 6). In any case, in embodiment 700auxiliary burners 750, 752 serve to push foam layer 719 towardprojections 718, and may provide flame that extends into side channels722, 724 to heat the outer portions of the molten glass stream.Roof-mounted auxiliary burner 754 is illustrated schematically asmounted via an adjustable mount 732, such as a ceramic-lined ballturret, in roof 708, and causes its combustion products to impinge onthe “stacked up” foam layer 719 and burst at least some of the bubblesin foam layer 719 through heat and/or hitting the foam bubbles directly.

It should be understood that embodiment 700 is only one example of manypossible downstream components and channel shapes. Suitable shapedchannel or trough 702 of refractory material may have any longitudinalshape (straight, L-shaped, curved, for example S-shaped), and may haveone or more parallel and/or series arranged regions. Trough 702 may haveany lateral (cross-sectional) shape, such as rectangular, oval, round,V-shaped, U-shaped, and the like. Depth of trough 702 may vary, butexemplary embodiments may have a depth that is commensurate with SCmelter depth, and such that the foamy molten glass will be able to moveinto the trough. The cross-sectional shape may be the same or differentalong the length of the trough.

The flow rate of the foamy or reduced foam molten glass through trough702 will in turn depend on many factors, including the dimensions oftrough 702, size of SC melter 602, whether or not there is a weir orlike device (such as a skimmer hanging from a roof of trough 702),temperature of the melts, viscosity of the melts, and like parameters,but in general the flow rate of molten glass in trough 702 may rangefrom about 0.5 lb./min to about 5000 lbs./min or more (about 0.23 kg/minto about 2300 kg/min or more), or from about 10 lbs./min to about 500lbs./min (from about 4.5 kg/min to about 227 kg/min), or from about 100lbs./min to 300 lbs./min (from about 45 kg/min to about 136 kg/min).

FIGS. 8-10 are logic diagrams of four method embodiments of the presentdisclosure. FIG. 8 is a logic diagram of method embodiment 800,including the steps of melting glass-forming materials in a submergedcombustion melter comprising a floor, a roof, and a wall structureconnecting the floor and roof, the melter comprising one or moresubmerged combustion burners and a molten glass outlet (box 802);producing an initial foamy molten glass having a density and comprisingbubbles, at least some of the bubbles forming a bubble layer on top ofthe foamy molten glass (box 804); and routing combustion products fromone or more non-submerged auxiliary burners positioned in the roofand/or wall structure to impact at least a portion of the bubbles in thebubble layer with sufficient force and/or heat to burst at least some ofthe bubbles and form a reduced foam molten glass, (box 806).

FIG. 9 is a logic diagram of method embodiment 900, which comprises thesteps of melting glass-forming materials in a submerged combustionmelter comprising a floor, a roof, and a wall structure connecting thefloor and roof, the melter comprising one or more submerged combustionburners and a molten glass outlet, (box 902); producing an initial foamymolten glass having a density and comprising bubbles, at least some ofthe bubbles forming a bubble layer on top of the foamy molten glass,(box 904); routing at least a portion of the foamy molten glass andbubble layer into a downstream component fluidly connected to themelter, the downstream component comprising a flow channel, a downstreamcomponent roof, and a downstream component wall structure connecting thedownstream component flow channel and downstream component roof, (box906); and routing combustion products from at least one downstreamcomponent non-submerged auxiliary burner positioned in the downstreamcomponent roof and/or downstream component wall structure to impact atleast a portion of bubbles in the bubble layer on the foamy molten glasswith sufficient force and/or heat to burst at least some of the bubbles,(box 908).

FIG. 10 is a logic diagram of method embodiment 1000, which is a methodcomprising the steps of melting glass-forming materials in a submergedcombustion melter comprising a floor, a roof, and a wall structureconnecting the floor and roof, the melter comprising one or moresubmerged combustion burners and a molten glass outlet, (box 1002);producing an initial foamy molten glass having a density and comprisingbubbles, at least some of the bubbles forming a bubble layer on top ofthe foamy molten glass, (box 1004); routing combustion products from oneor more non-submerged auxiliary burners positioned in the roof and/orwall structure to impact at least a portion of the bubbles in the bubblelayer with sufficient force and/or heat to burst at least some of thebubbles and form a reduced foam molten glass, (box 1006); routing atleast a portion of the reduced foam molten glass to a downstreamcomponent fluidly connected to the melter, the downstream componentcomprising a flow channel, a downstream component roof, and a downstreamcomponent wall structure connecting the downstream component flowchannel and downstream component roof, (box 1008), and routingcombustion products from one or more non-submerged downstream componentauxiliary burners positioned in the downstream component roof and/ordownstream component wall structure to impact at least a portion ofbubbles remaining in the bubble layer on the reduced foam molten glasswith sufficient force and/or heat to burst at least some of theremaining bubbles, (box 1010).

Submerged combustion melter 602 in embodiments described herein may beany of the currently known submerged combustion melter designs, or maybe one of those described in Applicant's U.S. Pat. No. 8,769,992,incorporated herein by reference. Submerged combustion melters useful inthe practice of the methods and apparatus of this description may takeany number of forms, including those described in Applicant's U.S. Pat.No. 8,769,992, which describes sidewalls forming an expanding meltingzone formed by a first trapezoidal region, and a narrowing melting zoneformed by a second trapezoidal region, wherein a common base between thetrapezoid defines the location of the maximum width of the melter.Submerged combustion melter 602 may include a roof, side walls, a flooror bottom, one or more submerged combustion burners, an exhaust chute,one or more molten glass outlets, and optionally fluid-cooled panelscomprising some or all of the side walls. Submerged combustion melter602 is typically supported on a plant floor.

Submerged combustion melter 602 may be fed a variety of feed materialsby one or more roll stands, which in turn supports one or more rolls ofglass mat, as described in Applicant's U.S. Pat. No. 8,650,914,incorporated herein by reference. In certain embodiments powered niprolls may include cutting knives or other cutting components to cut orchop the mat (or roving, in those embodiments processing roving) intosmaller length pieces prior to entering melter 602. Also provided incertain embodiments may be a glass batch feeder. Glass batch feeders arewell-known in this art and require no further explanation. Certainembodiments may comprise a process control scheme for the submergedcombustion melter and burners. For example, as explained in the '970application, a master process controller may be configured to provideany number of control logics, including feedback control, feed-forwardcontrol, cascade control, and the like. The disclosure is not limited toa single master process controller, as any combination of controllerscould be used. The term “control”, used as a transitive verb, means toverify or regulate by comparing with a standard or desired value.Control may be closed loop, feedback, feed-forward, cascade, modelpredictive, adaptive, heuristic and combinations thereof. The term“controller” means a device at least capable of accepting input fromsensors and meters in real time or near—real time, and sending commandsdirectly to burner control elements, and/or to local devices associatedwith burner control elements and glass mat feeding devices able toaccept commands. A controller may also be capable of accepting inputfrom human operators; accessing databases, such as relational databases;sending data to and accessing data in databases, data warehouses or datamarts; and sending information to and accepting input from a displaydevice readable by a human. A controller may also interface with or haveintegrated therewith one or more software application modules, and maysupervise interaction between databases and one or more softwareapplication modules. The controller may utilize Model Predictive Control(MPC) or other advanced multivariable control methods used in multipleinput/multiple output (MIMO) systems. As mentioned previously, themethods of Applicant's U.S. Pat. No. 8,973,400, using the vibrations andoscillations of the melter itself, may prove useful predictive controlinputs.

Those having ordinary skill in this art will appreciate that there aremany possible variations of the melter, channels, troughs, burners, andadjustment mechanisms to adjust combustion product direction describedherein, and will be able to devise alternatives and improvements tothose described herein that are nevertheless considered to be within theclaims of the present patent.

Submerged combustion burners useful in the SC melter apparatus describedherein include those described in U.S. Pat. Nos. 4,539,034; 3,170,781;3,237,929; 3,260,587; 3,606,825; 3,627,504; 3,738,792; 3,764,287; and7,273,583, and Applicant's U.S. Pat. No. 8,875,544. One useful burner,for example, is described in the 583 patent as comprising a method andapparatus providing heat energy to a bath of molten material andsimultaneously creating a well-mixed molten material. The burnerfunctions by firing a burning gaseous or liquid fuel-oxidant mixtureinto a volume of molten material. The burners described in the 583patent provide a stable flame at the point of injection of thefuel-oxidant mixture into the melt to prevent the formation of frozenmelt downstream as well as to prevent any resultant explosivecombustion; constant, reliable, and rapid ignition of the fuel-oxidantmixture such that the mixture burns quickly inside the molten materialand releases the heat of combustion into the melt; and completion of thecombustion process in bubbles rising to the surface of the melt. In oneembodiment, the burners described in the 583 patent comprises an innerfluid supply tube having a first fluid inlet end and a first fluidoutlet end and an outer fluid supply tube having a second fluid inletend and a second fluid outlet end coaxially disposed around the innerfluid supply tube and forming an annular space between the inner fluidsupply tube and the outer fluid supply tube. A burner nozzle isconnected to the first fluid outlet end of the inner fluid supply tube.The outer fluid supply tube is arranged such that the second fluidoutlet end extends beyond the first fluid outlet end, creating, ineffect, a combustion space or chamber bounded by the outlet to theburner nozzle and the extended portion of the outer fluid supply tube.The burner nozzle is sized with an outside diameter corresponding to theinside diameter of the outer fluid supply tube and forms a centralizedopening in fluid communication with the inner fluid supply tube and atleast one peripheral longitudinally oriented opening in fluidcommunication with the annular space between the inner and outer fluidsupply tubes. In certain embodiments, a longitudinally adjustable rod isdisposed within the inner fluid supply tube having one end proximate thefirst fluid outlet end. As the adjustable rod is moved within the innerfluid supply tube, the flow characteristics of fluid through the innerfluid supply tube are modified. A cylindrical flame stabilizer elementis attached to the second fluid outlet end. The stable flame is achievedby supplying oxidant to the combustion chamber through one or more ofthe openings located on the periphery of the burner nozzle, supplyingfuel through the centralized opening of the burner nozzle, andcontrolling the development of a self-controlled flow disturbance zoneby freezing melt on the top of the cylindrical flame stabilizer element.

The location of the injection point for the fuel-oxidant mixture belowthe surface of the melting material enhances mixing of the componentsbeing melted and increases homogeneity of the melt. Thermal NO_(x)emissions are greatly reduced due to the lower flame temperaturesresulting from the melt-quenched flame and further due to insulation ofthe high temperature flame from the atmosphere.

In certain embodiments the SC burners may be floor-mounted burners. Incertain embodiments, the SC burners may be positioned in rowssubstantially perpendicular to the longitudinal axis (in the melt flowdirection) of melter 602. In certain embodiments, the SC burners may bepositioned to emit combustion products into molten glass in a meltingzone of melter 6022 in a fashion so that the gases penetrate the meltgenerally perpendicularly to the floor. In other embodiments, one ormore burners may emit combustion products into the melt at an angle tothe floor, as taught in Applicant's U.S. Pat. No. 8,769,992.

Submerged combustion melters useful in systems and methods in accordancewith the present disclosure may also comprise one or more wall-mountedsubmerged combustion burners, and/or one or more roof-mounted(non-auxiliary) burners. Roof-mounted burners may be useful to pre-heatthe melter apparatus melting zone, and serve as ignition sources for oneor more submerged combustion burners. Melters having only wall-mounted,submerged-combustion burners are also considered within the presentdisclosure. Roof-mounted burners may be oxy-fuel burners, but as theyare only used in certain situations, are more likely to be air/fuelburners. Most often they would be shut-off after pre-heating the melterand/or after starting one or more submerged combustion burners. Incertain embodiments, if there is a possibility of carryover of particlesto the exhaust, one or more roof-mounted burners could be used to form acurtain to prevent particulate carryover. In certain embodiments, allsubmerged combustion burners are oxy/fuel burners (where “oxy” meansoxygen, or oxygen-enriched air, as described earlier), but this is notnecessarily so in all embodiments; some or all of the submergedcombustion burners may be air/fuel burners. Furthermore, heating may besupplemented by electrical heating in certain melter embodiments, incertain melter zones, and in the lehr. In certain embodiments theoxy-fuel burners may comprise one or more submerged combustion burnerseach having co-axial fuel and oxidant tubes forming an annular spacethere between, wherein the outer tube extends beyond the end of theinner tube, as taught in U.S. Pat. No. 7,273,583, incorporated herein byreference. Burners may be flush-mounted with the melter floor in certainembodiments. In other embodiments, such as disclosed in the '583 patent,a portion of one or more of the burners may extend slightly into themelt above the melter floor.

In certain embodiments, melter side walls may have a free-flowing form,devoid of angles. In certain other embodiments, side walls may beconfigured so that an intermediate location may comprise an intermediateregion of melter 602 having constant width, extending from a firsttrapezoidal region to the beginning of a narrowing melting region. Otherembodiments of suitable melters are described in the above-mentioned'754 application.

As mentioned herein, useful melters may include refractory fluid-cooledpanels. Liquid-cooled panels may be used, having one or more conduits ortubing therein, supplied with liquid through one conduit, with anotherconduit discharging warmed liquid, routing heat transferred from insidethe melter to the liquid away from the melter. Liquid-cooled panels mayalso include a thin refractory liner, which minimizes heat losses fromthe melter, but allows formation of a thin frozen glass shell to form onthe surfaces and prevent any refractory wear and associated glasscontamination. Other useful cooled panels include air-cooled panels,comprising a conduit that has a first, small diameter section, and alarge diameter section. Warmed air transverses the conduits such thatthe conduit having the larger diameter accommodates expansion of the airas it is warmed. Air-cooled panels are described more fully in U.S. Pat.No. 6,244,197. In certain embodiments, the refractory fluidcooled-panels are cooled by a heat transfer fluid selected from thegroup consisting of gaseous, liquid, or combinations of gaseous andliquid compositions that functions or is capable of being modified tofunction as a heat transfer fluid. Gaseous heat transfer fluids may beselected from air, including ambient air and treated air (for airtreated to remove moisture), inert inorganic gases, such as nitrogen,argon, and helium, inert organic gases such as fluoro-, chloro- andchlorofluorocarbons, including perfluorinated versions, such astetrafluoromethane, and hexafluoroethane, and tetrafluoroethylene, andthe like, and mixtures of inert gases with small portions of non-inertgases, such as hydrogen. Heat transfer liquids may be selected frominert liquids which may be organic, inorganic, or some combinationthereof, for example, salt solutions, glycol solutions, oils and thelike. Other possible heat transfer fluids include steam (if cooler thanthe oxygen manifold temperature), carbon dioxide, or mixtures thereofwith nitrogen. Heat transfer fluids may be compositions comprising bothgas and liquid phases, such as the higher chlorofluorocarbons.

The refractory or refractory-lined channels or troughs described inaccordance with the present disclosure may be constructed usingrefractory cooled panels. Both the melter and trough floors and sidewalls may include a thin refractory lining, as discussed herein. Thethin refractory coating may be 1 centimeter, 2 centimeters, 3centimeters or more in thickness, however, greater thickness may entailmore expense without resultant greater benefit. The refractory liningmay be one or multiple layers. Alternatively, melters and channelsdescribed herein may be constructed using cast concretes such asdisclosed in U.S. Pat. No. 4,323,718. The thin refractory liningsdiscussed herein may comprise materials described in the 718 patent. Twocast concrete layers are described in the 718 patent, the first being ahydraulically setting insulating composition (for example, that knownunder the trade designation CASTABLE BLOC-MIX-G, a product ofFleischmann Company, Frankfurt/Main, Federal Republic of Germany). Thiscomposition may be poured in a form of a wall section of desiredthickness, for example a layer 5 cm thick, or 10 cm, or greater. Thismaterial is allowed to set, followed by a second layer of ahydraulically setting refractory casting composition (such as that knownunder the trade designation RAPID BLOCK RG 158, a product of Fleischmanncompany, Frankfurt/Main, Federal Republic of Germany) may be appliedthereonto. Other suitable materials for the refractory cooled panels,melter and channel refractory liners, and refractory block burners (ifused) are fused zirconia (ZrO₂), fused cast AZS(alumina-zirconia-silica), rebonded AZS, or fused cast alumina (Al₂O₃).The choice of a particular material is dictated among other parametersby the melter geometry and type of glass to be produced.

The total quantities of fuel and oxidant used by the SC burners insystems of the present disclosure may be such that the flow of oxygenmay range from about 0.9 to about 1.2 of the theoretical stoichiometricflow of oxygen necessary to obtain the complete combustion of the fuelflow. Another expression of this statement is that the combustion ratiomay range from about 0.9 to about 1.2. In certain embodiments, theequivalent fuel content of the feed material must be taken into account.For example, organic binders in glass fiber mat scrap materials willincrease the oxidant requirement above that required strictly for fuelbeing combusted. In consideration of these embodiments, the combustionratio may be increased above 1.2, for example to 1.5, or to 2, or 2.5,or even higher, depending on the organic content of the feed materials.

The velocity of the fuel gas in the various SC burners depends on theburner geometry used, but generally is at least about 15 m/s. The upperlimit of fuel velocity depends primarily on the desired mixing of themelt in the melter apparatus, melter geometry, and the geometry of theburner; if the fuel velocity is too low, the flame temperature may betoo low, providing inadequate melting, which is not desired, and if thefuel flow is too high, flame might impinge on the melter floor, roof orwall, and/or heat will be wasted, which is also not desired.

For auxiliary burners burning natural gas, the auxiliary burners mayhave a fuel firing rate ranging from about 10 to about 1000 scfh (fromabout 280 L/hr. to about 28,000 LAO; an oxygen firing rate ranging fromabout 15 to about 2500 scfh (from about 420 L/hr. to about 71,000L/hr.); a combustion ratio ranging from about 1.5 to about 2.5; nozzlevelocity ratio (ratio of velocity of fuel to oxygen at the fuel nozzletip) ranging from about 0.5 to about 2.5; fuel gas velocity ranging fromabout 150 to about 1000 ft./sec (from about 46 m/sec to about 300m/sec); and oxygen velocity ranging from about 150 to about 1000 ft./sec(from about 46 m/sec to about 300 m/sec). Of course these numbers dependon the heating value of the fuel, amount of oxygen in the “oxygen”stream, temperatures and pressures of the fuel and oxidant, and thelike, among other parameters. In one typical operation, the auxiliaryburner would have a combustion ration of 2.05:1; a velocity ratio of 1;firing rate of natural gas of 500 scfh (14,000 L·hr.) and 1075 scfh(30,400 L/hr.) oxygen; natural gas and oxygen velocities each of 270ft./sec (80 m/sec); natural gas pressure of 1 psig (6.9 KPa); and oxygenpressure of 0.6 psig (4.1 Kpa), pressures measured at the entrance tothe combustion chamber.

Although only a few exemplary embodiments of this disclosure have beendescribed in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel apparatus andprocesses described herein. Accordingly, all such modifications areintended to be included within the scope of this disclosure as definedin the following claims. In the claims, no clauses are intended to be inthe means-plus-function format allowed by 35 U.S.C. §112, paragraph 6unless “means for” is explicitly recited together with an associatedfunction. “Means for” clauses are intended to cover the structuresdescribed herein as performing the recited function and not onlystructural equivalents, but also equivalent structures.

What is claimed is:
 1. A system comprising: a submerged combustionmelter comprising a floor, a roof, and a wall structure connecting thefloor and roof, the melter comprising one or more submerged combustionburners and a molten glass outlet, the melter configured to produce aninitial foamy molten glass having a density and comprising bubbles, atleast some of the bubbles forming a bubble layer on top of the foamymolten glass; and one or more non-submerged auxiliary burners positionedin the roof and/or wall structure and configured to deliver theircombustion products to impact at least a portion of the bubbles in thebubble layer with sufficient force and/or heat to burst at least some ofthe bubbles and form a reduced foam molten glass.
 2. The system of claim1 comprising one or more auxiliary burners protruding through the wallstructure and one or more auxiliary burners protruding through the roof.3. The system of claim 2 comprising a downstream component fluidlyconnected to the melter for accepting at least a portion of the reducedfoam molten glass, the downstream component comprising a flow channel, adownstream component roof, and a downstream component wall structureconnecting the flow channel and downstream component roof, thedownstream component comprising one or more non-submerged downstreamcomponent auxiliary burners positioned in the downstream component roofand/or the downstream component wall structure and configured to delivercombustion products to impact at least a portion of bubbles remaining ina bubble layer on the reduced foam molten glass, if any, with sufficientforce and/or heat to burst at least some of the remaining bubbles.
 4. Asystem comprising: a submerged combustion melter comprising a floor, aroof, and a wall structure connecting the floor and roof, the meltercomprising one or more submerged combustion burners and a molten glassoutlet, the melter configured to produce an initial foamy molten glasshaving a density and comprising bubbles, at least some of the bubblesforming a bubble layer on top of the foamy molten glass; and adownstream component fluidly connected to the melter for accepting atleast a portion of the foamy molten glass, the downstream componentcomprising a flow channel, a downstream component roof, and a downstreamcomponent wall structure connecting the downstream component flowchannel and downstream component roof, the downstream componentcomprising one or more non-submerged downstream component auxiliaryburners positioned in the downstream component roof and/or downstreamcomponent wall structure and configured to deliver their combustionproducts to impact at least a portion of bubbles in the bubble layer onthe foamy molten glass with sufficient force and/or heat to burst atleast some of the bubbles.
 5. The system of claim 4 wherein one or moreof the non-submerged forehearth auxiliary burners are liquid-cooledpipe-in-pipe burners.
 6. The system of claim 4 wherein one or more ofthe non-submerged downstream component auxiliary burners comprise a fuelinlet conduit having an exit nozzle, the conduit and nozzle insertedinto a cavity of a ceramic burner block, the ceramic burner block inturn inserted into either the downstream component roof or thedownstream component wall structure, or both the downstream componentroof and the downstream component wall structure.
 7. The system of claim5 wherein the pipe-in-pipe burner comprises a first conduit and a secondconduit concentric with and outside of the first conduit, the firstconduit fluidly connected at one end to a source of fuel, and the secondconduit fluidly connected to a source of oxidant.
 8. The system of claim4 wherein one or more of the non-submerged downstream componentauxiliary burners is adjustable with respect to direction of flow of thecombustion products.
 9. A method comprising: melting glass-formingmaterials in a submerged combustion melter comprising a floor, a roof,and a wall structure connecting the floor and roof, the meltercomprising one or more submerged combustion burners and a molten glassoutlet; producing an initial foamy molten glass having a density andcomprising bubbles, at least some of the bubbles forming a bubble layeron top of the foamy molten glass; and routing combustion products fromone or more non-submerged auxiliary burners positioned in the roofand/or wall structure to impact at least a portion of the bubbles in thebubble layer with sufficient force and/or heat to burst at least some ofthe bubbles and form a reduced foam molten glass.
 10. The method ofclaim 9 comprising adjusting one or more of the non-submerged auxiliaryburners with respect to direction of flow of their combustion products.11. The method of claim 9 comprising flowing at least a portion of thereduced foam molten glass to a downstream component fluidly connected tothe melter, the downstream component comprising a flow channel, adownstream component roof, and a downstream component wall structureconnecting the downstream component wall structure and downstreamcomponent roof.
 12. The method of claim 11 comprising routing combustionproducts from at least one non-submerged downstream component auxiliaryburners positioned in the downstream component roof and/or downstreamcomponent wall structure to impact at least a portion of bubblesremaining in the reduced foam molten glass.
 13. The method of claim 12comprising adjusting one or more of the non-submerged downstreamcomponent auxiliary burners with respect to direction of flow of theircombustion products.
 14. The method of claim 9 comprising adjusting fuelvelocity of the auxiliary burners to a value ranging from about 150ft./second to about 1000 ft./second (about 46 meters/second to about 305meters/second) and adjusting oxidant velocity to a value ranging fromabout 150 ft./second to about 1000 ft./second (about 46 meters/second toabout 305 meters/second), wherein the fuel and oxidant velocities may bethe same or different.
 15. A method comprising: melting glass-formingmaterials in a submerged combustion melter comprising a floor, a roof,and a wall structure connecting the floor and roof, the meltercomprising one or more submerged combustion burners and a molten glassoutlet; producing an initial foamy molten glass having a density andcomprising bubbles, at least some of the bubbles forming a bubble layeron top of the foamy molten glass; and routing at least a portion of thefoamy molten glass and bubble layer into a downstream component fluidlyconnected to the melter, the downstream component comprising a flowchannel, a downstream component roof, and a downstream component wallstructure connecting the downstream component flow channel anddownstream component roof; and routing combustion products from at leastone downstream component non-submerged auxiliary burners positioned inthe downstream component roof and/or downstream component wall structureto impact at least a portion of bubbles in the bubble layer on the foamymolten glass with sufficient force and/or heat to burst at least some ofthe bubbles.
 16. The method of claim 15 comprising adjusting one or moreof the downstream component non-submerged auxiliary burners with respectto direction of flow of their combustion products.
 17. The method ofclaim 16 comprising adjusting fuel velocity of the downstream componentnon-submerged auxiliary burners to a value ranging from about 150ft./second to about 1000 ft./second (about 46 meters/second to about 305meters/second) and adjusting oxidant velocity to a value ranging fromabout 150 ft./second to about 1000 ft./second (about 46 meters/second toabout 305 meters/second), wherein the fuel and oxidant velocities may bethe same or different.
 18. A method comprising: melting glass-formingmaterials in a submerged combustion melter comprising a floor, a roof,and a wall structure connecting the floor and roof, the meltercomprising one or more submerged combustion burners and a molten glassoutlet; producing an initial foamy molten glass having a density andcomprising bubbles, at least some of the bubbles forming a bubble layeron top of the foamy molten glass; routing combustion products from oneor more non-submerged auxiliary burners positioned in the roof and/orwall structure to impact at least a portion of the bubbles in the bubblelayer with sufficient force and/or heat to burst at least some of thebubbles and form a reduced foam molten glass; and routing at least aportion of the reduced foam molten glass to a downstream componentfluidly connected to the melter, the downstream component comprising aflow channel, a downstream component roof, and a downstream componentwall structure connecting the downstream component flow channel anddownstream component roof; and routing combustion products from one ormore non-submerged downstream component auxiliary burners positioned inthe downstream component roof and/or downstream component wall structureto impact at least a portion of bubbles remaining in the bubble layer onthe reduced foam molten glass with sufficient force and/or heat to burstat least some of the remaining bubbles.
 19. The method of claim 18comprising adjusting one or more of the non-submerged auxiliary burnersin the melter roof and/or melter wall structure with respect todirection of flow of their combustion products.
 20. The method of claim18 comprising adjusting one or more of the downstream componentnon-submerged auxiliary burners with respect to direction of flow oftheir combustion products.
 21. The method of claim 18 comprisingadjusting the melter auxiliary burners to have a fuel velocity rangingfrom about 150 ft./second to about 1000 ft./second (about 46meters/second to about 305 meters/second) and an oxidant velocityranging from about 150 ft./second to about 1000 ft./second (about 46meters/second to about 305 meters/second), wherein the fuel and oxidantvelocities may be the same or different.
 22. The method of claim 18comprising adjusting the downstream component auxiliary burners to havea fuel velocity ranging from about 150 ft./second to about 1000ft./second (about 46 meters/second to about 305 meters/second) and anoxidant velocity ranging from about 150 ft./second to about 1000ft./second (about 46 meters/second to about 305 meters/second), whereinthe fuel and oxidant velocities may be the same or different.